1974 Gibson Houseboat-Twin MerCruiser 255 Hp Electric shift issue

[switzer-stache]

1. PORT side-operates well. It has Forward, Nuetral and Reverse.
2. STBD side-doesn't go into forward.
3. Both shift actuators operate in the same manner, so electrically from the helm to the actuator-everything is in working condition.
4. Boat is in water, so if there's anything else that i need to check that might be the possible cause of the problem; please let me know
5. Owner stated the dipstick was about 2 quarts low two weeks ago and added accordingly. Went to the boat last night and it was a quart low. It seems there is a leak somewhere, but even top'd off and running the drive still has no forward.

I'm not familiar with anything pre 1980's (I'm a younger marine mechanic), but am very versitile in my work. Anyone with an idea of the direction i should go now, before pulling the boat out of the water, please let me know. Thank you and I'll continue to research/document any findings for future reference

 

[picklenjim]

Re: 1974 Gibson Houseboat-Twin MerCruiser 255 Hp Electric shift issue

What you have is a TR drive with a Merc-Trans transmission. First off those trannys only hold 2 quarts. Beings the electric shift motor is working the problem would be in the trans. The fluid from the pump is not making it to the piston to apply the clutch pack or the clutch pack is worn beyond tolerances. Reverse is achieved by a band tightening around the planetary/drum and has nothing to do with forward except for the fact that it gets it's pressure from the same pump. I rebuilt one for a guy last year with the same problem. The teflon sealing rings on the output shaft which direct fluid to the forward piston were trashed/gone. Also tore up the surface where they seal on the piston housing.The rings are #80 and the piston housing is #89 in the diagram.
http://www.perfprotech.com/store/as...LY-(STERN-DRIVE)-PAGE-2,988-220.aspx#assembly
Unfortunately these transmissions have not been made since around 1980 and parts are pretty much unavailiable.
There is a guy that sells these rebuilt with new bearings and seals and clutchs and also sells used parts, at new price.
http://www.kcmarinetr.com/Default.aspx
He has one on ebay right now.
http://cgi.ebay.com/ebaymotors/merc...at_Parts_Accessories_Gear&hash=item3f0ab81b5f
All the info on rebuilding one is in Mercury Service Manual #1...Section 6 Drive System....Part G. Actually their pretty simple.
Soooo if the shift actuator is operating fully in both directions there is nothing else you can do at this point. You know the pump is working because you still have reverse. Sorry to say but the boat will need to be pulled,drive removed,engine and trans pulled. You will need to fix that one or get a rebuilt one or find a used one. If you look for a used one be sure to specify Ford or Chevy. Internals are the same-bellhousings are different. Where are you located? I may be of assistance as I have a few of these for parts and as said I rebuild them.

 

[switzer-stache]

Re: 1974 Gibson Houseboat-Twin MerCruiser 255 Hp Electric shift issue

Son of a gun, another "floating-condo for the summer!" lol I had a feeling that was the case. Well, thanks for the response PICKLENJIM, I truely appeciate it. Shoot me a direct email address to get ahold of you-I'm 110% sure the customer isn't gonna want to do this until "haul-out" season, beings he just bought the boat this spring and it's his first houseboat purchase! I took a look at the links you posted (very informative) and with the condition the boat is in vs. the dollar amount of boat's value, it's going to be a hard one to convince this boater...but it never hurts to ask! I'm curious to know about how long did it take to rebuild the TR trans you encountered? I'm leaning towards a rebuilt (for warranty purposes) but by looking at the components involved in the rebuild, it could be worth my time to take a stab at it as well...if i can get ahold of some parts, or coarse. Thanks again PICKLENJIM